DIY Doctor UK DIY Forums

Hi, we are having problems with our hot water cylinder. Its taking about 4 hours to heat enough for a quick shower and once you turn off the immersion it will be cold in minutes even with a new lagging jacket.

We have had a plumber and an electrician in to look at it and they installed a new element, jacket, thermostat and still the problem. I am thinking maybe there is too quick of a cold feed, only recently the cold feed pipe has become very wet and ice cold. Could that be an issue? The guys are baffled and so am I. Any ideas?

Thanks

A lagged water cylinder will keep the water at least warm for 24 hours. If the water is cooling then only one thing is happening. It is leaving the cylinder. Either you have a running hot tap somewhere or there is a hidden leak draining the hot water.

Typical symptoms are stone cold feed pipe. The water in the header tank is not there long enough for the water temp to rise to ambient temp. Condensation is typical too. The area around the cylinder is wet because of the leak and the moist air forms condensation easily.

Live in a bungalow? Pipes go under the concrete floor? Turn off the cold water and watch the header tank empty even though all taps are off.

Hi, I live in an apartment on ground floor. Just a 2 floor building. And yes there are no taps running but i dont see a leek any where. The only water i see in the closet is the dripping condensation from the ice cold feed pipe. I turned off the immersion after 5 hours yesterday and within 20 minutes there was no hot water.

Do you mean shut off the cold water supply to the tank?

Thanks for your reply.

Hi
If you isolate the mains water supply to the cold water tank and have no taps running the level of water should remain the same. If it starts to drop then the water must be going somewhere which indicates a leak.
If the water level isnt dropping then the heat must be escaping from the hot water cylinder - assuming it gets in there in the first place. A hot water cylinder with no insulation should retain heat for longer than you describe. A leak does seem the only logical explanation if you are confident the immersion is working as it should.

Yes I mean turn off the supply to the header tank. If the water is draining away as the symptoms suggest, the tank will be constantly filling and as soon as you turn it off, the tank will start to empty. Leave it for an hour or two.

I hope you don't have a water meter?

Thanks for your help Plumbbob abd Barry.It sounds very logical what you say. I dont know if i have access to the header tank but i will check it out.

Hi the Smiths

you may have a leak in the coil in the cylinder ??

Regards

Skids

Thanks skids. I couldn't get access to the header tank so i turned off the cold water feed and waited to see if the cylinder began to empty, i didn't wait the full 2 hours or so but waited about half an hour before turning it back on. And when i did turn it back on there was definite sound of the cylinder filling back up for a few moments. Without using any water during this time my guess is all you guys are right about a leek somewhere, otherwise the cylinder wouldn't need to refill would it?

Are you on gas or are you on electric?

There will definately be a leak either in the cylinder or the pipework.

Is the immersion actually heating the water up? Could there be a wiring problem?

[b]Hi, I had this problem a couple of years ago.Mine turned out to be the mixer tap on the bath was passing cold water into the hot water system.I hope this helps someone out there ![/b]

gas central heating and electric immersian. They are both able to heat the water but takes so long to do it. If anything the gas heating provides better results but the tank would still go cold in 20 minutes of turning it off. Looks like there must be a leek underground somewhere so they will be coming in later this week to start digging up the concrete floors to find it.